The first vein grown from a patient’s own stem cells was successfully transplanted into a 10-year-old girl, potentially offering a way for those lacking healthy veins to undergo dialysis or heart bypass surgery. A team led by Michael Olausson of the University of Gothenburg took a 9-centimeter (3.5-inch) segment of vein from a human donor and removed all living cells, the Swedish researchers wrote in a study in The Lancet medical journal today. The resulting protein scaffolding was injected with stem cells from the girl’s bone marrow, and two weeks later was implanted in the patient, who had a blockage in the vein that carries blood from the spleen and intestines to the liver.